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Succinic semialdehyde dehydrogenase deficiency: GABAB receptor-mediated function.
- Source :
-
Brain research [Brain Res] 2006 May 23; Vol. 1090 (1), pp. 15-22. Date of Electronic Publication: 2006 May 02. - Publication Year :
- 2006
-
Abstract
- The succinic semialdehyde dehydrogenase (SSADH) null mouse (SSADH(-/-)) represents a viable animal model for human SSADH deficiency and is characterized by markedly elevated levels of both gamma-hydroxybutyric acid (GHB) and gamma-aminobutyric acid (GABA) in brain, blood, and urine. In physiological concentrations, GHB acts at the GHB receptor (GHBR), but in high concentrations such as those observed in the brains of children with SSADH deficiency, GHB is thought to be a direct agonist at the GABABR receptor (GABABR). We tested the hypothesis that both GHBR and GABABR-mediated function are perturbed in SSADH deficiency. Therefore, we examined the high affinity binding site for GHB as well as the expression and function of the GABABR in mutant mice made deficient in SSADH (SSADH(-/-)). There was a significant decrease in binding of the specific GABABR antagonist, [3H]CGP-54626A at postnatal day (PN)7 and PN14 in SSADH(-/-) when compared to wild type control animals (SSADH(+/+)), particularly in hippocampus. GABABR-mediated synaptic potentials were decreased in SSADH(-/-). Immunoblot analysis of GABABR1a, R1b, and R2 in SSADH(-/-) indicated a trend towards a region-specific and time-dependent decrease of GABABR subunit protein expression. There was no difference between SSADH(-/-) and wild type in binding of either [3H]GHB or a specific GHBR antagonist to the GHBR. These data suggest that the elevated levels of GABA and GHB that occur in SSADH(-/-) lead to a use-dependent decrease in GABABR-mediated function and raise the possibility that this GHB- and GABA-induced perturbation of GABABR could play a role in the pathogenesis of the seizures and mental retardation observed in SSADH deficiency.
- Subjects :
- Animals
Binding Sites genetics
Brain physiopathology
Brain Diseases, Metabolic, Inborn genetics
Brain Diseases, Metabolic, Inborn physiopathology
Disease Models, Animal
GABA Antagonists pharmacology
Hydroxybutyrates metabolism
Mice
Mice, Knockout
Protein Subunits genetics
Receptors, GABA-B genetics
Synaptic Transmission drug effects
Synaptic Transmission genetics
Up-Regulation genetics
gamma-Aminobutyric Acid metabolism
Brain enzymology
Brain Chemistry genetics
Brain Diseases, Metabolic, Inborn enzymology
Receptors, GABA-B metabolism
Succinate-Semialdehyde Dehydrogenase deficiency
Succinate-Semialdehyde Dehydrogenase genetics
Subjects
Details
- Language :
- English
- ISSN :
- 0006-8993
- Volume :
- 1090
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Brain research
- Publication Type :
- Academic Journal
- Accession number :
- 16647690
- Full Text :
- https://doi.org/10.1016/j.brainres.2006.02.131